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5 PRELIMINARY INFORMATION
5.7.3 Reading the R2 buffer memory
When reading the R2 buffer memory using the transmission/reception buffer, after the
control data is written to the transmission buffer, the data is read from the buffer
memory by turning the intelligent device station access request (complete) signal
(RY(n+1)E, RX(n+1)E) ON and OFF.
(1) Flow of process
R2
Programmable controller CPU Master station
1) Control data
Bit device
Word device
Remote
input (RX)
Remote
output (RY)
Remote
output (RY)
Remote
input (RX)
Buffer
memory
5) Intelligent device station access
complete ON
7) Intelligent device station access
complete OFF
2) Intelligent device station access
request ON
6) Intelligent device station access
request OFF
Transmission
buffer
Reception
buffer
* When using the RIRD (RIRCV) command,
the steps 2) to 7) are carried out automatically.
3) Read command
8) Reception data 4) Control data + reception data
(2) Timing chart
1)
2)
3)
4)
5)
6)
7)
8)
Carried out with sequence program
Carried out b
y
R2
Intelligent device station access
request signal (RY(n+1)E)
Intelligent device station access
complete signal (RX(n+1)E)
Programmable controller CPU
word device
Master station
transmission buffer
Master station
reception buffer
R2 buffer memory
No. Details Control side
1) The control data is written to the master station transmission buffer. Program
2) The intelligent device station access request signal (RY(n+1)E) turns ON. Program
3) The contents set in the control data are conveyed to the R2. R2
4) The control data is stored in the master station reception buffer. R2
5) The intelligent device station access complete signal (RX(n+1)E) turns ON. R2
6) The intelligent device station access request signal (RY(n+1)E) turns OFF. Program
7) The intelligent device station access complete signal (RX(n+1)E) turns OFF. R2
8) The reception data is read from the master station reception buffer. Program